1. Field of the Invention
This invention relates to packaging for dilute hypochlorite compositions, especially containers provide stability to dilute hypochlorite and hypochlorous acid compositions.
2. Description of the Related Art
U.S. Pat. Appl. 2002/0179884 to Hoshino et al. found that low concentration hypochlorite compositions present difficulties in obtaining a formulation with satisfactory storage stability. This is because loss of 100 ppm available chlorine in a 5% hypochlorite composition is usually not critical, but the same loss in a composition with 150 ppm available chlorine might be unexceptable. Hoshino lists several factors that affect the storage stability of dilute hypochlorite compositions, but offers no packaging solutions. U.S. Pat. No. 6,426,066 to Najafi et al. describes containers for oxidized water. Glass containers were preferred over HDPE or Teflon®.
U.S. Pat. No. 6,586,063 to Albanesi et al. describes stable multilayer containers for concentrated hypochlorite. The preferred outer layer for the container was PP or PET. The preferred inner layer was LDPE or LLDPE. The multilayer container could also be stabilized against permeation of hypochlorite by including a barrier layer of MDPE, HDPE, or EVOH. U.S. Pat. No. 5,080,826 to Colborn et al. describes containers for fragranced concentrated hypochlorite. The preferred container material is HDPE for its molding properties, rather than for stability. Colburn mentions various other additives, such as colorants, opacifying agents, antioxidants, and plasticizing agents, but there is no concern about these additives for hypochlorite stability.
No hypochlorite products currently exist in aerosol type containers or delivery devices which generate small droplet size. U.S. Pat. App. 2003/0186827 to Makansi describes an aerosol container for concentrated hypochlorite. The preferred inner liner for the container is polyethylene or polypropylene. Dilute hypochlorite presents even more difficulty in achieving sufficient stabitlity. We have found the lined aerosol cans do not provide sufficient stability to dilute hypochlorite compositions. Makansi also describes an aerosol dispenser where the hypochlorite composition and the propellant are injected inside a flexible pouch. We have found that dilute hypochlorite compositions do not have sufficient stability in the same pouch with propellant.
Based on the prior art examples, the need exists for containers for dilute hypochlorite that can give suitable storage stability. Various novel containers and container materials for hypohalous acid, hypohalous acid salt, and compositions containing these actives have been discovered.